1. Field of the Invention
This invention relates to the use of certain terminal-group-blocked alkylpolyethylene glycolethers in aqueous polymer dispersions and latices for foam inhibitors, emulsification, and/for stabilization.
2. Statement of the Related Art
German patent publication No. 33 15 951 (Henkel case D6859), which corresponds to U.S. application Ser. No. 601,475, and is incorporated herein by reference, relates to the use of polyethylene glycolethers corresponding to the formula EQU R.sub.1 --O--(CH.sub.2 CH.sub.2 O).sub.n --R.sub.2 (I)
in which R.sub.1 is a straight-chain or branched C.sub.8-18 alkyl or alkenyl, R.sub.2 is a C.sub.4-8 alkyl, and n is a number from 7 to 12, as foam-inhibiting additives for low-foam cleaning preparations. The foam inhibitors in question are particularly intended for use in cleaning preparations for commerce and industry which includes the cleaning of metal, glass, ceramic and plastic surfaces. Compared with foam-inhibiting additives based on adducts of aklyene oxides of inorganic compounds containing reactive hydrogen atoms in the molecule as known from: U.S. Pat. No. 3,491,029 (and corresponding German patent publication No. 12 80 455), British patent publication No. 1,172,135 (and corresponding German patent publication No. 16 21 592); U.S. Pat. Nos. 3,463,737 and 3,491,029 (and corresponding German patent publication No. 12 89 597); British patent publication No. 1,172,134 (and corresponding German patent publication No. 16 21 593); and U.S. Pat. No. 3,696,057 (and corresponding German patent publication No. 19 44 569); the compounds corresponding to general formula I are distinguished by the fact that, in addition, they are biologically degradable, their biological degradability being determined by German governmentally stipulated methods as being equivalent to a BiAS removal of more than 80%.
In addition, German patent publication No. 33 15 951 describes in use of the polyethylene glycolethers corresponding to general formula I in admixture with polyethlene glycolethers of the type obtained by addition of from 4 to 20 parts by weight of ethylene oxide onto 1 part by weight of polyglycerol having a hydroxyl number of from 900 to 1200 and subsequent etherification of the free hydroxyl groups with C.sub.4-8 alkyl halides. The preparation of polyglycerol/ethylene oxide ethers such as these and their use is the subject of U.S. Pat. No. 4,522,740 (and corresponding German patent publication No. 33 15 952).
As contrasted with detergent systems, the present invention provides improved aqueous polymer dispersions and latices and method for their preparation. Aqueous polymer dispersions and corresponding latices obtained by emulsion polymerization are used for a variety of commercial applications, for example as binder dispersions which are exposed to various stresses during transport and storage and in use. Polymer dispersions of the type in question are, basically, highly sensitive, unstable 2-phase systems which in practice are exposed to numerous destabilizing influences under utilization conditions. The stabilization of polymer dispersions and latices (i.e. in particular the prevention of undesirable creaming or coagulation), involves a complex set of problems for which many and various solutions have already been proposed. For example, polymer dispersions or emulsions of the type in question have to be protected against coagulation by freezing and thawing, and from the shear forces or other forces encountered during their formulation into emulsion paints, coating compositions, emulsion plasters, leather finishes, polishes, adhesives, textile auxiliaries, and the like. Nonionic surfactants, such as fatty alcohols, fatty acids, alkylphenol or fatty amine polyglycolethers, are mostly used for these stabilizing functions, although they generally promote foaming in the system and, in many cases, also show unsatisfactory biodegradability.
In the field of emulsion polymerization, there is a continuous search for new surfactants which show favorable properties both in the preparation of the emulsion and during the polymerization reaction, and particularly in regard to the properties of the polymer latex formed. This is made particularly difficult insofar as it is not possible to draw any reliable conclusions based upon the chemical structure of a surfactant as to its properties as a polymerization emulsifier or stabilizer.